La CAPSULE A DES FUITES !! (on trouve une solution) Ep.2
Articles,  Blog

La CAPSULE A DES FUITES !! (on trouve une solution) Ep.2


Hello everyone and welcome in this second episode
of the Capsule program. In the last episode, we told you about
the preparation and the training which was done inside the lagoon
to handle the ballasts here in the Bay of Opunohu. Today, we are going to install the ballasts
on the site that we had scouted during the last episode. So, let me get ready and join
the rest of the crew on the WHY and let’s go diving! We start the operations. We let the air out of the ballasts, we let the water in,
and they start to sink slowly. We descend, we come close to the bottom,
and at the same time we navigate through what will be our garden for the next
few months. It’s a rich garden with great biodiversity,
rich in corals with pocillopora that we have studied throughout last year
during the DeepHope program and that is home to a rich life. These yellowtail damselfish are hovering
on top of their habitat, whilst the myripristis who find
shelter inside those caves or cavities inside coral heads. For the last centimetres, we are positioning
the ballast very precisely and then we open the valve to let all the air out,
water is flooding the ballast, which comes down to touch on one side. We lay it flat exactly
where we wanted to it to be. We install the second ballast the same way,
and put it down right besides the first one. Once installed in its final position,
we finish to let the air out which releases a great amount of bubbles,
whilst the water is coming in. They become extremely heavy,
and these will become our anchors to install the Capsule just above. It’s a great moment, the ballasts are in the water,
and next it will be the Capsule. So we are are going to assemble the domes of the Capsule, which require to tighten 50 nuts in a precise manner to make it completely
watertight. During this operation, we need to be accurate and patient. – Lucky that you are paccurate… – Paccurate and accient, that’s right! Especially me: I’m really patient,
everyone knows that! We are close to the end, we’ve assembled the domes and have done the torque tightening so tomorrow we’ll perform and hydraulic test
by filling up this aquarium with water and we’ll cross our fingers it won’t leak. So, you’re probably wondering
what we’re about to do here. Because filling up the Capsule with water can be counter intuitive.
But by doing so, we are replicating the exact same stress that the Capsule will be under
whilst filled up with air in the ocean. Let me explain in more details. When we immerse the Capsule in the ocean,
water will put pressure on the Capsule itself and intuitively one could think that this pression would crush the Capsule. But in fact, we have the same exact pressure between the atmosphere and the water in the lower part which is where the moon pool is,
and there is a higher pressure on the top part which means that the stress will come from the inside towards the outside on the dome level. This is why if we turn around the Capsule 180º
and fill it up with water we are seeing the exact same efforts applied to the domes, pushing them outwards. So now, let’s go back to the episode. And another one… It’s continuous now. It’s a strainer… It means that we have a lot of work to make adjustments, because we need to spot all the leaks, empty the Capsule, correct all the issues, fill it up again, and hope that all problems
will be fixed. We are adding a sort of thick paste on the nut thread and under the bolt in order to create a filling and stop
the water from leaking. We corrected all the leaks, we did a kind
of crash-test by shaking all of the bolts to see if all of them were strong enough,
and we managed to fix all the issues. So now we can say that we’ve done it! It’s really cool. The Capsule is now watertight which is a good news and now we have to focus on the electronics and on what we call
the atmospheric control system. When we’ll be inside the Capsule,
we’ll breath a gas mix made of oxygen and helium. We’ll use up the oxygen gradually and
just like a rebreather we use we need to offset this loss of oxygen by a regular injection of oxygen.
But we also need to absorb the CO2 in the Capsule by using scrubbers of lime soda which will be set up inside the Capsule. No off-the-shelf solution existed on the market,
so we asked Sylvain to develop one,
so let’s go find him to talk about it. The electronics of the Capsule start here with 3 oxygen solenoids. These solenoids send the information
and injection controller. This controller centralises all the data,
and from them, will trigger the injection of the right quantity
of oxygen at the right time to compensate for the divers’ consumption. The oxygen injector sends information to the switch which is the central communication hub
of the Capsule. Here we have a multi-gas analyser,
which monitors in redundancy the level of oxygen, of CO, of carbon dioxyde and helium. This analyser also sends information to the switch. The third element which is plugged into the switch
is a video camera which also has a microphone. So to sum up, the switch centralises the data from
the oxygen injector, the multi-gas analyser and the video camera. All the data is sent through a cable via an antenna at the surface and is transmitted to the station on-land
from which we can visually monitor the divers ’round the clock, as well as
all the atmospheric parameters of the Capsule. We are here to do a test of the inside fit-outs,
so we’re putting inside the Capsule every single thing that we will have
to have in reality once underwater. I’m telling you right now: I’m not taking this one, guys! What are you thinking when you see Sylvain squashed like that? I’m thinking that I’d take the other bed, you see! Better not be claustrophobic! Yeah, you’re right! Is he really asleep? Yes, he’s really sleeping. It’s actually bigger than I thought
so It’s a pleasant surprise. I don’t see any problem
spending time in there. 3 weeks? Maybe not 3 weeks, but 3 days for sure! So let me take you inside the Capsule,
to show you where we’ll live and how we’re set up! Here we have a bench
which is also a bed, this one here is a chair back, but we can
make it horizontal and make it a bunk bed. The camera is on one end of the dome,
which gives you a bit of a perspective! Here we have the oxygen injector, which
is the critical piece of control of the atmosphere, and here are the 2 scrubbers,
which are filled with lime soda, and we have a small fan to force the air inside the filter, plus it will
help the atmosphere circulate inside the Capsule. You see, I’m crawling a bit and behind me you can see a small dive tank which
will be used in case of an emergency to allow to get out of the Capsule quickly
and get to the emergency deco line. It shouldn’t happen, but still, we’re ready for it. So the Capsule like you’re seeing it
is actually finished and ready. It is in its final configuration like it will be underwater
with all the monitors, screens, solenoids, filters… The immersion of the Capsule, its installation
of the Capsule on its final site is what we’ll tell you in the next episode. I hope that you enjoyed this one. Don’t forget to subscribe
and see you soon. Nana!

3 Comments

Leave a Reply

Your email address will not be published. Required fields are marked *